Universal air bubble detector

Abstract

A universal air bubble detector allows for use with a variety of sizes and types of tubing. The detector maintains proper alignment of a sensor emitter and receiver with different sizes of tubing. The detector may be mounted on existing equipment or may be used to monitor a tubing at any position along the tubing, and may operate in a stand alone mode or in combination with existing equipment.

1. An air bubble detector comprising:
 a housing configured to receive a conduit; 
 a piezoelectric emitter; 
 a piezoelectric receiver; and 
 wherein at least one of the piezoelectric emitter and receiver comprises a plurality of piezoelectric elements disposed in a gapless array; and 
 wherein the piezoelectric emitter comprises a plurality of piezoelectric elements disposed in an array generally perpendicular to the lumen of the conduit, and wherein the detector is configured for sequential firing of the plurality of piezoelectric elements to thereby steer an emitted ultrasonic signal. 
 
     
     
       2. The detector of  claim 1 , wherein the array of piezoelectric elements is curved to match somewhat the curvature of a conduit which is loaded into the housing. 
     
     
       3. An air bubble detector comprising:
 a housing configured to receive a conduit; 
 a piezoelectric emitter; 
 a piezoelectric receiver; and 
 wherein the piezoelectric emitter and receiver are disposed so as to be on opposite sides of a conduit when the conduit is loaded into the housing and wherein at least one of the emitter and receiver comprise a pedestal of material disposed between the piezoelectric element and the conduit so as to transmit ultrasonic signals between the piezoelectric element and the conduit, wherein the pedestal is smaller in cross-sectional area than the piezoelectric element in a plane perpendicular to the path of transmission of ultrasonic signals, and further comprising a region adjacent the pedestal which does not transmit ultrasonic signals such that transmission of ultrasonic signals between the piezoelectric element and the conduit is limited to transmission through the pedestal. 
 
     
     
       4. An air bubble detector comprising:
 a housing configured for receiving a conduit; 
 a piezoelectric emitter having a planar ceramic material with conductive metal layers on two opposing sides thereof; 
 a piezoelectric receiver having a planar ceramic material with conductive metal layers on two opposing sides thereof; 
 wherein the piezoelectric emitter and receiver are disposed so as to be oriented towards each other and on generally opposite sides of a conduit which is loaded into the housing; and 
 at least one spring disposed to hold at least one of the emitter and receiver in place in the housing, the at least one spring being disposed in contact with one of said conductive metal layers so as to form an electrical contact therewith. 
 
     
     
       5. The detector of  claim 4 , wherein the at least one spring holds the at least one of the emitter and receiver by pressing against a first side thereof such that a second side thereof opposite the first side thereof is pressed against an electrical conductor to thereby make electrical contact therewith. 
     
     
       6. An air bubble detector comprising:
 a housing configured for receiving a conduit; 
 a piezoelectric emitter; 
 a piezoelectric receiver; 
 wherein the emitter and receiver comprise generally planar elements which are disposed so as to be generally parallel to each other and so as to be disposed on generally opposite sides of a conduit which is loaded into the housing so as to transmit ultrasonic signals between the emitter and receiver; and 
 further comprising a pedestal disposed between the conduit housing and a piezoelectric element selected from the emitter and receiver, the pedestal being formed of a material which transmits ultrasonic signals and being smaller in cross sectional area than said piezoelectric element taken along a plane perpendicular to the path of ultrasonic transmission between the conduit and said piezoelectric element such that transmission of ultrasonic signals between the emitter and the receiver is limited to a cross-sectional size smaller than the emitter and receiver. 
 
     
     
       7. The detector of  claim 6 , wherein the pedestal comprises a raised section of the housing which contacts said piezoelectric element to thereby transmit the signal from said one of the emitter and receiver. 
     
     
       8. The detector of  claim 7 , further comprising at least one recessed area adjacent the raised section, said at least one recessed area being configured to not touch said one of the emitter and receiver to thereby form a gap so as to not transmit the signal from said piezoelectric element. 
     
     
       9. The detector of  claim 8 , wherein the at least one recessed area is covered by a mask which does not transmit ultrasonic signals. 
     
     
       10. The detector of  claim 9 , wherein the mask is an air impregnated material.